With the bullet detection I used a simple function to detect when the enemies were hit, you can take a look at it: camera > functions > isHit.

It is very useful in an FPS as when lag gets worse it still functions well.

The pausing can be made better but I was to lazy... lol normally I use a function that lets no enemies move or you move when its turned on, but its a little hard when you wanted to add that feature after making a lot of the game... lol.